Computational fluid dynamics analysis and optimization of highway savonius wind turbine integrated with guide vanes

Abstract

Substantial efforts have been made by researchers to study the interaction between vortices produced by moving vehicles and wind turbines as a renewable energy source. The speeding vehicles produced a scattered and non-uniform wind flow. A curtain system was placed in front of the wind turbine blade to reduce the negative torque. However, it has limitation where high wind energy losses occur when passing through the curtain system arrangement. The aim of this study was to improve further the performance of wind by designing a capable Highway Savonius Wind Turbine (HSWT) integrated with a curtain system. It consists of a row guide vane with an aerofoil shape of National Advisory Committee for Aeronautics (NACA) 4412. In addition, a Computational Fluid Dynamics (CFD) modelling of a reliable HSWT integrated with guide vanes was also employed. Three factors, namely, the distance between the guide vanes (dGV), the guide vanes angle (a), and the moving car speed (VC) were selected to evaluate their influence on the HSWT power coefficient (Cp). Taguchi Method with an orthogonal array of L9(33) was used to plan and conduct the simulations. The CFD simulations with one degree of freedom were performed using k-? SST turbulence model to observe the effects of the wind velocity induced by the moving vehicle in real-life situation. The influence strength of each factor was VC > a > dGV where the ranks were 3.53, 8.86 and 9.33, respectively. It was found that, the performance of HSWT was sensitive to the car speed and the guide vanes angle, but insensitive to the distance between the guide vanes. The signal to noise ratio showed that combination of dGV = 0.4m, a = 30°, and VC =30m/s produced the maximum power coefficient. This optimum condition increased the power coefficient by 26% compared to without the installation of the guide vanes. In addition, the observation of streamline and velocity contours showed that guide vanes demonstrate a positive effect on the wind turbine performance by redirecting and distributing the turbulence wake flow uniformly to the convex surface of the advancing turbine blade. Hence, the proposed guide vanes system improved the self-starting abilities of HSWT by reducing negative torque.